Earth
290
The rotation of Earth is slowing down, so
days are becoming longer. In the age of
the dinosaurs, 60 million years ago, an
Earth day was less than 23 hours long.At midnight on 21 June each year, it is
light everywhere north of the Arctic Circle.Looking out to sea from the beach, the
horizon is about 5 km (3 miles) away.
Fresh snow is more than
90 per cent trapped air.
After it was measured using satellites in 1999, the
official height of Mount Everest was raised from
8,848 m (29,029 ft) to 8,850 m (29,035 ft).The Great Barrier Reef, at more than
2,000 km (1,200 miles) long, is the largest
living structure on Earth. It is even visible
from space.Nine out of ten volcanoes are under the
sea. More than 1,000 of the 1,500 active
volcanoes in the world are in
the South Pacific Ocean.When the volcanic
island of Krakatoa,
in Indonesia, erupted in
1883 , it could be heard
a quarter of the way
around the world.In 1811 , an
earthquake sent
water in the
Mississippi River
flowing temporarily in
the wrong direction.
China’s Yellow River is
the world’s muddiest
river. Two billion tonnes
of mud wash down it
every year.
The strongest gust
of wind ever recorded
blew at 372 km/h
(231 mph) on Mount
Washington, USA,
in 1934.
The pressure at the centre of
Earth is 3 million times greater
than that at the surface.
In the 20
th
century, the surfacetemperature of Earth rose by 0.6
0
C (1
0
F).Almost 20 per cent of Earth’s oxygen is
produced by the Amazon rainforest.There are about 750
different species of tree in
one hectare (2.47 acres) of
the Amazon rainforest.
It would take a heavy object more than an
hour to sink from the surface to the seabed
at Challenger Deep in the Pacific Ocean,
which is 11,034 m (36,201 ft) deep.A large thunderstorm cloud,
called a cumulonimbus,
can hold enough water to
fill 500,000 baths.Over half the planet is covered by
water more than 1.6 km (1 mile) deep.Six million tonnes of gold are
dissolved in the water of the world’s oceans.The volume of water in the Pacific
Ocean is the same size as the Moon.Lightning strikes Earth 100 times every second.The driest continent is Antarctica because it receives so little rain.
The biggest desert in
the world, the Sahara,
covers a third of the
area of Africa.
The driest place in the world is the Atacama Desert
in Chile. When it rained there in 1971 , it ended a
drought that had lasted for 400 years.Sand dunes move like waves across deserts
at a speed of about 1 m (3 ft) per year.The lowest temperature ever recorded is -89.2^0 C
(-128.5^0 F) at Vostok, Antarctica, on 21 July 1983.The highest temperature ever
recorded was 56.7^0 C (134.1^0 F)
at Furnace Creek, California,
on 10 July 1913.Coal
is made from
the compressed
remains of plants
that died
300 million
years ago.
290_291_EarthFacts.indd 290 03/01/19 12:11 PM